Computer-implemented method for making a skeleton of a modeled body take a posture

Abstract

A computer-implemented method for making a skeleton of a modeled human or animal body take a posture, including obtaining a first and a second skeleton each comprising rotational joints connected by bones, each rotational joint of the second skeleton being associated to a respective joint of the first skeleton, determining a relative configuration of the second skeleton, mapping each joint of the first skeleton to a joint of the second skeleton, making the first skeleton take a posture defined by a rotational state for each joint of the first skeleton, and computing transformation matrices for the joints of the second skeleton such that a change is minimized, said second skeleton further including a prismatic joint on at least one of its bones, and determining rotations of the rotational joints and translation of the prismatic joint or joints of the second skeleton such that change is minimized.

The invention claimed is: 
     
       1. A computer-implemented method for making a skeleton of a modeled human or animal body takes a posture, comprising:
 a) obtaining a first skeleton and a second skeleton of at least one digital body model, each of said first skeleton and said second skeleton including a plurality of rotational joints connected by bones, the first skeleton having a greater number of rotational joints than the second skeleton, each rotational joint of the second skeleton being associated to a respective joint of the first skeleton: 
 b) determining a relative configuration of the second skeleton, said relative configuration mapping each joint of the first skeleton, associated with a joint of the second skeleton, to said joint of the second skeleton; 
 c) based on one or more inputs from a user, making the first skeleton take a posture defined by a rotational state for each joint of the first skeleton; and 
 d) computing transformation matrices for the joints of the second skeleton such that a relative configuration of the second skeleton remains unchanged, 
 wherein said second skeleton further includes a prismatic joint on at least one bone of the second skeleton, 
 wherein step d) further includes determining rotations of the rotational joints and translation of the prismatic joint or joints of the second skeleton such that the relative configuration of the second skeleton remains unchanged, and 
 wherein the first skeleton and the second skeleton belong to a same digital body model. 
 
     
     
       2. The method of  claim 1 , wherein the second skeleton includes a prismatic joint on all bones of the second skeleton. 
     
     
       3. The method of  claim 1 , wherein step d) further includes computing a transformation matrix for each joint of the second skeleton by considering said joints in succession, starting from a root joint. 
     
     
       4. The method of  claim 1 , wherein step a) further includes making the first and the second skeleton take respective initial postures. 
     
     
       5. The method of  claim 1 , further comprising:
 e) applying the computed transformation matrices to the joints of the second skeleton, making the second skeleton take a posture matching that of the first skeleton. 
 
     
     
       6. The method of  claim 5 , further comprising:
 f) displaying, on a computer screen, at least one of the second skeleton and of a skin associated with the second skeleton. 
 
     
     
       7. A non-transitory computer-readable data-storage medium containing computer-executable instructions that when executed by a computer system cause the computer system to carry out the method according to  claim 1  for making the skeleton of the modeled human or animal body take the posture. 
     
     
       8. The non-transitory computer readable medium of  claim 7 , wherein the second skeleton includes a prismatic joint on all bones of the second skeleton. 
     
     
       9. The non-transitory computer readable medium of  claim 7 , wherein step d) further includes computing a transformation matrix for each joint of the second skeleton by considering said joints in succession, starting from a root joint. 
     
     
       10. The non-transitory computer readable medium of  claim 7 , wherein step a) further includes making the first and the second skeleton take respective initial postures. 
     
     
       11. The non-transitory computer readable medium of  claim 7 , wherein the method further comprises:
 e) applying the computed transformation matrices to the joints of the second skeleton, making the second skeleton take a posture matching that of the first skeleton. 
 
     
     
       12. The non-transitory computer readable medium of  claim 11 , wherein the method further comprises:
 f) displaying, on a computer screen, at least one of the second skeleton and of a skin associated with the second skeleton. 
 
     
     
       13. The non-transitory computer readable medium of  claim 7 , wherein the first skeleton and the second skeleton belong to a same digital body model. 
     
     
       14. A computer system comprising;
 a processor coupled to a memory and a graphical user interface, the memory storing computer-executable instructions that when executed by the processor cause the processor to be configured to 
 obtain a first skeleton and a second skeleton of at least one digital body model, each of said first skeleton and said second skeleton including a plurality of rotational joints connected by bones, the first skeleton having a greater number of rotational joints than the second skeleton, each rotational joint of the second skeleton being associated to a respective joint of the first skeleton, 
 determine a relative configuration of the second skeleton, said relative configuration mapping each joint of the first skeleton, associated with a joint of the second skeleton, to said joint of the second skeleton, 
 make, based on one or more inputs from a user, the first skeleton take a posture defined by a rotational state for each joint of the first skeleton, and 
 compute transformation matrices for the joints of the second skeleton such that a relative configuration of the second skeleton remains unchanged, 
 wherein said second skeleton further includes a prismatic joint on at least one bone of the second skeleton, 
 wherein the processor is further configured to determine the relative configuration of the second skeleton by being configured to determine rotations of the rotational joints and translation of the prismatic joint or joints of the second skeleton such that the relative configuration of the second skeleton remains unchanged, and 
 wherein the first skeleton and the second skeleton belong to a same digital body model. 
 
     
     
       15. A digital body model comprising:
 a first skeleton and a second skeleton, each of said first and second skeleton comprising a plurality of rotational joints connected by bones, the first skeleton having a greater number of rotational joints than the second skeleton, each rotational joint of the second skeleton being associated to a respective joint of the first skeleton, 
 wherein said second skeleton further comprises a prismatic joint on at least one bone of the second skeleton, and 
 wherein the first skeleton and the second skeleton belong to a same digital body model. 
 
     
     
       16. The digital body model of  claim 15 , wherein the second skeleton includes a prismatic joint on all bones of the second skeleton.